The Rotary Dial Telephone
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The first phones had no dial. With switchboards staffed by operators, dials were not needed. But automated systems required something like a dial to enable numbers to be sent to the exchange. The first practical rotary dial was invented in 1898 (US patent No. 597,062). This was by the prolific Alexander Keith and the Erickson brothers. Some credit Almon Strowger (US patent 486,909) with the first dial. However, his version needed 5 wires from the telephone to the central office so was not practical and little used compared to Keith's dial.
Over the next ~25 years the dial continued to be improved with the "numbers plus letters" dial introduced in New York City in 1922. See Note below.
Dialing causes the line current to be interrupted (e.g., 5 pulses for the digit 5). These pulses are then counted by exchange relays or other recording methods. With a dial, no operator was needed for local calls.
Rotary dial, circa 1900. This dial was circular like the fully mature dial but instead of holes, it had lugs on a finger plate for the user to grab and rotate.
This model is from the Science Museum of London, UK.
The “Candlestick” phone, featuring a dial with numbers and letters, was introduced in the early 1920s
From 1930 to about 1940 the
type-D handset was popular.
100’s of millions of dial phones were made.
Touch Tone dials (keypad) began replacing the pulse dial in 1963.
Source: Paul-F
Since Alexander Graham Bell's time, thousands of telephone varieties have emerged. Some are pedestrian designs while others are exotic. Since about 2014, AI generated art has been available. Imagine if Leonardo Da Vinci created a dial telephone, how might it look?
Here are few examples of phone designs created by the DALL-E 2 generative art service. There are many sites devoted to vintage telephones. The coverage here is the very tip of the iceberg. See the excellent Telephone Collectors International (TCI) site; www.telephonecollectors.org for a wealth of resources.
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Notes:
For a deeper dive, see "Early Work on Dial Telephone Systems" by R.B. Hill, Bell Laboratories Record, Jan 1953, page 22.
Also, see the article Bell's first transmitter and the important work of Francis Blake in the same article.
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